SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9143314868b55db74082f732f6440a8b2237326775d9bb630a4bc99bd8a9171' 
  AND token = '+E7gY74DBYmOW8JRvh1FfDzwq+xh8ZRlWkZiN5FWn0s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}